net: dsa: resolve tagging protocol at parse time

Extend the dsa_port_parse_cpu() function to resolve the tagging protocol
at port parsing time, instead of waiting for the whole tree to be
complete.
Signed-off-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/dsa2.c

@@ -511,8 +511,23 @@ static int dsa_port_parse_dsa(struct dsa_port *dp)
 
 static int dsa_port_parse_cpu(struct dsa_port *dp, struct net_device *master)
 {
+	struct dsa_switch *ds = dp->ds;
+	struct dsa_switch_tree *dst = ds->dst;
+	const struct dsa_device_ops *tag_ops;
+	enum dsa_tag_protocol tag_protocol;
+
+	tag_protocol = ds->ops->get_tag_protocol(ds);
+	tag_ops = dsa_resolve_tag_protocol(tag_protocol);
+	if (IS_ERR(tag_ops)) {
+		dev_warn(ds->dev, "No tagger for this switch\n");
+		return PTR_ERR(tag_ops);
+	}
+
 	dp->type = DSA_PORT_TYPE_CPU;
+	dp->rcv = tag_ops->rcv;
+	dp->tag_ops = tag_ops;
 	dp->master = master;
+	dp->dst = dst;
 
 	return 0;
 }
@@ -521,25 +536,9 @@ static int dsa_cpu_parse(struct dsa_port *port, u32 index,
 			 struct dsa_switch_tree *dst,
 			 struct dsa_switch *ds)
 {
-	const struct dsa_device_ops *tag_ops;
-	enum dsa_tag_protocol tag_protocol;
-
 	if (!dst->cpu_dp)
 		dst->cpu_dp = port;
 
-	tag_protocol = ds->ops->get_tag_protocol(ds);
-	tag_ops = dsa_resolve_tag_protocol(tag_protocol);
-	if (IS_ERR(tag_ops)) {
-		dev_warn(ds->dev, "No tagger for this switch\n");
-		return PTR_ERR(tag_ops);
-	}
-
-	dst->cpu_dp->tag_ops = tag_ops;
-
-	/* Make a few copies for faster access in master receive hot path */
-	dst->cpu_dp->rcv = dst->cpu_dp->tag_ops->rcv;
-	dst->cpu_dp->dst = dst;
-
 	return 0;
 }